LONDON (Reuters) - Uncertainty over drug regulation and a reluctance by Britain’s health service to use certain pricey modern medicines pose a threat to the country’s respected life sciences sector, the head Swiss drugmaker Roche said on Thursday.

With only six months to go until the United Kingdom is due to leave the European Union, the highly regulated pharmaceuticals industry still does not know exactly how medicines oversight will function.

Severin Schwan, chief executive of the world’s biggest maker of cancer drugs, said in an interview that Europe was already slower than the United States to approve new medicines and there are fears the UK might fall further behind, jeopardizing investment.

“The UK would get markedly less competitive and less interesting for the industry as a life science hub,” he told Reuters. “For us, this is a very relevant question and if the regulatory system should not keep up with Europe, then this would be a big issue for us.”

Roche employs 2,100 staff in Britain and has been in the country since 1908. Staff work not only in the commercial business but also in a substantial drug development operation.

“It goes without saying that we give preference in research and development activities where we bring the medicines to patients first,” Schwan said.

“Even though we very much appreciate the science and capabilities in the UK, it is not possible to disconnect that from access to innovative medicines.”

Schwan noted that the UK could, in theory, use Brexit to create an independent drugs regulator that was faster than the European Medicines Agency. However, he also said this would require large government investment in both staff and resources.

In addition to uncertainty over the licensing of medicines, Schwan is also frustrated by curbs on access to some treatments within Britain’s National Health Service.

His company is in a bitter row over the health service’s refusal to approve Ocrevus, the company’s new drug for treating a highly disabling form of multiple sclerosis.

“We now have a situation where patients in need don’t get the medicine. It’s as simple as that,” Schwan said.

In preparation for potential supply disruption in the event of Britain leaving the EU without a deal with Brussels, the government has told drugmakers to build an additional six weeks of medicine stockpiles.

Schwan said that Roche is increasing its stocks in line with peers and would be able to continue to supply patients in the event of a no-deal Brexit.

Additional reporting by John Miller in Zurich; Editing by David Goodman